On Sat, 24 Apr 2004 10:52:52 -0500, Wm. Freddy Curtis wrote:
>The problem that he has is that it will be located on the second story
>of his house. He is in great need of information for this station.
I don't consider myself an expert on lightning protection, so I will
defer to others for that. My station is on the second floor of my wood
frame house in a Chicago neighborhood. I do NOTHING special at all
beyond what I would normally do in a basement.
That is,
1) I try to use good antennas and use feedlines that don't put RF in
the shack.
2) I use wiring techniques to interconnect equipment that don't couple
RF into that equipment. Two of the most important are
a) terminating cable shields to equipment chassis, NOT to some internal
trace on a PC board; and
b) using shielded twisted pairs for audio and data I/O. For example,
the RS232 cable that connects my computer to my radios is made with
shielded CAT5 cable.
3) My connection to earth consists of multiple runs of AWG #8, each to
a different ground electrode, all of which are bonded together outside
the house. Each run has series inductance, and the multiple runs in
parallel reduces the total impedance that a lightning transient would
see.
Now, I have taken pains to get a good connection to "earth ground" for
my station, but that is for lightning protection and to provide a
counterpoise for an antenna that I load as an end-fed long wire on 160
(and the feedpoint is in my shack). And I would do no different if it
were in the basement. This antenna puts lots of RF in my shack, by
virtue of a current node at the low impedance feedpoint, hence #2a and
b above are important.
EMC guru Neil Muncy (ex-W3WJE) says, "Have you ever seen one of those
747's taking off from your local airport trailing a ground wire? I
never have, yet the many radio systems on-board manage to work quite
well with no connection to earth whatsoever!"
Jim Brown K9YC
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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